Effects of Dietary Amino Acid Regimens on Live Performance and Processing Characteristics of Cobb MV × 700 Male and Female Broilers

Abstract

The magnitude and timing of broiler responses to dietary amino acid (AA) density can vary between sexes and among genetic lines. Two experiments (Exp) were conducted to determine the responsiveness of Cobb MV × 700 broilers to changes in dietary AA density. In Exp 1, low (L), medium (M), and high (H) AA density diets were maintained across starter and grower phases in a 28 d growth performance trial (all males). In Exp 2, combinations of L, M, and H-AA density diets were varied across 4 feeding phases to evaluate the effect of 6 AA feeding regimens (HHHH, HHHM, HHMM, HMMM, MMMM, and HHLL) on growth performance, carcass composition, and breast muscle myopathies of broilers reared sex-separately. Body weight gain, feed intake (FI), and FCR responded positively to increased AA density during the starter and grower phases (0 to 28 d) of Exp 1. In Exp 2, broiler responses to AA density from 0 to 28 d diminished by the conclusion of the finisher phase (day 35), and FCR was the only measurement influenced by dietary AA density through day 46. Carcass characteristics and breast muscle myopathies were unaffected by AA density, with the exception of fat pad percentage, which decreased with increasing AA density. These data indicate that Cobb MV × 700 broilers may be less responsive to dietary AA density than other high-yielding broiler strains and further research to establish digestible AA:Lys ratios or dietary energy concentrations that optimize responses to increased AA density are warranted.